1. Field of the Invention
The present invention relates to chemical sensing architectures and, more specifically, to a bacteriorhodopsin based chemical sensor.
2. Description of the Related Art
The motivating force behind sensor technology of any type is health. Whether it be defined in terms of human, machine, building, system, or the environment, health maintenance is critical in today's society. The factor to be sensed depends on the application; mechanical stress, pressure, temperature, light flux, and chemical or biological contamination are all common targets of sensor architectures. Perhaps the largest motivation in sensor technology development is found within the last two examples, the ability to detect compounds, toxins, or organisms deleterious to human health. A number of different sensor architectures are currently being explored, but the most prominent are efforts to mimic biological detection schemes. In an effort to model the mechanisms for biological chemical detection (i.e., smell and taste), researchers are moving away from specific detection interactions (favoring detection of a single chemical species or class of molecules), toward architectures that examine the collective responses of larger numbers of sensors that are characterized by non-specific molecular interactions. These technologies are typically referred to as electronic noses.
One approach to sensor design that has been explored very little to date, at least from the perspective of electronic nose technology, is that of hybrid architectures employing biological molecules as an active element of the detection scheme. There are several conceivable reasons as to why this approach has not been widely explored, such as stability and state determination. Complex biological molecules are not generally known for their inherent stability, and the ability to interrogate for the purpose of state determination requires some sort of signal transduction mechanism. Although many proteins act as signal transducers, few perform that function outside the confines of a biological organism and the transduction mechanisms that are employed inside the organism are not easily adapted to non-biological environments, at least not in a way that the signal of interest can be amplified and detected. One protein, Bacteriorhodopsin, or BR, does not suffer from these disadvantages, but has never been successfully adapted for use in a commercially viable sensor.